get a virgin sacrifice....

Kawah Ijen Volcano

Constantly spews sulfur in gas and liquid, lit up with bright blue flames, and has a lake of acid with pH down to 0.5. Gulleywhumper

Under the Sea...

Underwater caves would be pretty high up on my list, if not right up at the very top of it! The_Shape_Shifter

My dad used to cave dive! Made and sold videos of different underwater caves in Florida and Mexico. I breathed in his respirator once while I was above water and even that was too claustrophobic for me. He passed away several years ago, but his buddy spread his ashes in his favorite underwater cave. isakitty

The very true out back of Australia.

The very true outback of Australia. If you're traveling nobody expects to see you for up to a week, nobody expects phone calls or messages as theres no phone service. If you break down it could take a couple days until you are found by a passing car. And if they don't find you in time the dry extreme heat will kill you, you could never pack enough water to survive as long as it takes for someone to notice you're even missing. It's unforgiving and a horrible way to die. Not to mention that if you die the heat will decompose you in a matter of days and scavengers will scatter you meaning your family may never know. diggyminaj

The Canadian Arctic. 

The Canadian Arctic. The population density is 0.03 inhabitants/km2, and temperatures often drop to -50°C in the winter.

There are very few indigenous settlements, and the ones that are established rarely have a road to get to them. Icefields and glaciers have crevasses that can be up to 160 feet deep, and if you fall in deep enough or in a bad spot, there's a high likelihood that you'll die before any rescue team can reach you.

The northernmost national park, Quittinirpaaq, is 37,775 km2 and has 2 ranger stations. Your emergency radios may not even get a signal out due to weather, terrain, or solar activity. You are truly on your own in places that far north, and sometimes you'll have to bolt your tent down with steel cables because the winds will literally blow you away across the rocks.

One of the last truly wild places in the world simply because it is so harsh and unforgiving to humans, one misstep could kill you. It's amazing that Inuit have carved out their own world in such a place! HelpTheBirdsDude

the waters....

This is more eerie than scary, but towns that have been flooded to make a reservoir. The idea that there are people's belongings and houses down there, at the bottom of the lake, preserved in the cold water. silveralgea

Hisssss......

Snake Island.

Something crazy like 2 snakes per square meter. lol hazyyy5

In the Dark....

Any school at night with the lights off. Something about places that are alive with people all day can be the creepiest when you experience them alone in the dark at night.

Edit: I once got left in my old JR high building after a play. I had been playing hide and seek and stuff and when it was over my brother strait forgot to find me to go home. That stage, the auditorium, the curtains, back rooms with costumes. All that crap in the pitch dark and silence was crazy wild! Finiouss

 'The Lighthouse' 

After watching the movie 'The Lighthouse' I would be terrified of spending one day there. Just the idea of being in a small rock in the middle of nowhere with no communication and just one small accident from death terrifies me. GustavoAlex7789

The fun doesn't end there.

Aside from the well known places such as various death camps, prisons and battlefields.

Damn Poveglia island. Throughout the history it was used as quarantine zone during the plague outbreaks, there are multiple mass graves on site, supposedly it was just a dying ground for the afflicted, where at some places the very soil was purely composed of rotting plague corpses.

The fun doesn't end there. Later on someone decided to build a mental asylum right on top of that, in 1922. Countless cases of observed hauntings by the patients, but nobody believed them, since they were supposedly crazy. The headmaster of the institute then later on committed suicide by climbing the bell tower and jumping down. Mattiee

Leave Word.

La Rinconada, Perú. It's dangerous enough that you have to notify the cops of another town that you are going there. Gudrobilk